2018/02/28 by S. Kalyana Rama
Physics and Astronomy · #Anisotropy #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Equations of motion #Field (mathematics) #Function (biology) #Isotropy #Massless particle #Noncommutative and Quantum Gravity Theories #Scalar (mathematics) #Scalar field #gr-qc #hep-th
paper · pdf · doi:10.1007/s10714-018-2378-0
published as General Relativity and Gravitation (2018) 50:56 · Version 3. 33 pages. Minor change. To appear in General Relativity and Gravitation
openalex created_date 2018/03/06 · arxiv created 2018/05/07 · openalex publication_date 2018/05/07 · arxiv updated 2018/05/09 · openalex updated_date 2026/08/05
We explore whether generalised Brans -- Dicke theories, which have a scalar field Φ and a function ω(Φ), can be the effective actions leading to the effective equations of motion of the LQC and the LQC--inspired models, which have a massless scalar field σ and a function f(m) . We find that this is possible for isotropic cosmology. We relate the pairs (σ, f) and (Φ, ω) and, using examples, illustrate these relations. We find that near the bounce of the LQC evolutions for which f(m) = sin m, the corresponding field Φ→ 0 and the function ω(Φ) ∝ Φ2 . We also find that the class of generalised Brans -- Dicke theories, which we had found earlier to lead to non singular isotropic evolutions, may be written as an LQC--inspired model. The relations found here in the isotropic cases do not apply to the anisotropic cases, which perhaps require more general effective actions.